It is common in the solenoid valve art to provide a core tube of stainless steel or other like non-magnetic material around which a solenoid coil is mounted, and to mount a top plug or fixed armature part in the outer end of the core tube. The art is replete with examples of devices intended to hold a solenoid coil in place, in conjunction with the core tube construction.
In general, the core tubes are constructed either with a closed outer end, by a wall integral with the side wall of the core tube, or by a solid top plug, inserted in an opening along the outer end of the core tube. In the core tube without an integral top wall, the top plug usually is arranged to receive a screw, or is provided with an upwardly projecting threaded stud to take a nut, by which screw or nut the solenoid coil or housing is mounted against movement in the lengthwise direction of the core tube. In the closed ended tube, the core tube itself is grooved to receive a snap ring, or was threaded, as for example, in the to Pauli, U.S. Pat. No. 3,896,405, to receive a complementary threaded fastener. When the core tube is open ended, a leak path potentially exists from the axially inner portion of the core tube toward the outer end thereof. The potential for leakage along the core tube is undesirable in some applications of solenoid valves. The closed ended core tube constructions, while working for their intended purposes, often require time consuming constructional operations which raise overall product cost. To my knowledge, prior to my invention, no one has provided a core tube having an integral top wall with independent fastening means, thereby attaining simple, low cost core tube construction, non-leak path design and solenoid coil movement prevention.
One of the objects of this invention is to provide a solenoid valve structure in which the solenoid coil or housing can be mounted tightly in spite of substantial variation and height of the coil, the core tube, or the housing.
Another object of this invention is to provide such a structure which is easy to produce, economical, and rugged.
Another object of this invention is to provide a core tube having an integral top wall closing the outer end of the core tube with fastening means projecting axially outwardly of the outer end of the tube.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.